I have been listening and watching "Maestro Daniel Barenboim," truly one of the great artists of our time, perform all of Schubert's piano sonatas on Medici.tv. Schubert's sonatas are less structured than Beethoven's in many respects, but they contain a sense of improvisatory freshness.
One can feel in the music, at least I can, the sense of the moment of creation, as if he is a Jazz musician not knowing where the musical ideas will take him. For me, it's an emotional compositional ride down the musical rapids from a creative spirit! Schubert, the first song writer and Jazz Musician! Bravo! IMHO.
BTW, Schubert would write music from 6 am to 2 pm every day of his short life!